国内航空货物运价的种类有（）。
A.特种货物运价
B.等级货物运价
C.普通货物运价
D.起码运费
E.成组货物运价
参考答案：A, B, C, D, E
函数______返回值的含义是返回系统当前日期和当前时间。
— You look upset. What's the matter?
— I had my proposal (建议)____ again. [ ]
A. turned over
B. turned on
C. turned off
D. turned down
